davenbocafl

The answer is none at all. Changing a C4 to carb only gives you the advantage to controll more air flow that requires more fuel. There has been a beleife the FI is more fuel efficent, but the fact is it restricts the driver to put air into the motor. If you have the right fuel to air mixture on both, the engine is going to react the same, the cylinder doesnt know the difference.Its only you have more controll how much air you want to put in it,the more air you give it the more fuel it wants. So please some people dont say the fi is more efficent, Its the same, just gives the driver more options, on how much air you want to feed your beast. thank you for your induldgents. hehe

ps. the carb is much more dependable then leaky injectors or bad sencors and again we're the ole timers

vader86

aklim

How so? It is more efficient in that it allows you to control the fuel at all parts of the curve. Something that carbs do not. You can control timing at all points of the curve too. Either system uses throttle plates to control airflow. How does FI restrict the airflow?

How do you have more air control either way?

Is the carb also as flexible when adjusting fuel and timing? I think not. Sorry that the old timers cannot keep up with modern technology. Life moves on.

davenbocafl

Everybody knows that the c4's and others only increased mileage by restricking the air flow, A perfect example of that was the torgue to hp ratio. 260 HP with 330 torgue, everybody knew the ratio was way out of kilt. An efficient small block ,pretty well matched hp to torgue. such as 283/270 or 327/300hp or 325/350/365 or 350's/295/325/350/what ever. That was the efficentcy, sorry its just an air pump, what you put in you get out, yes you can run lean or rich, accually the motor likes lean for more HP but might burn a piston or two, all the same its not the gas but how much air you want, and keep your foot out of the throttle plates

The answer Aklim to more air controll is , you have to be a hoppeist

ps if you look like your pic, I'd love to take you out to dinner, I know shut up

aklim

Besides bad spelling and grammer, are you sure you got it right? You increase mileage by restricting airflow?

69427

geist

Ok so the engines were designed being purposly restrictive with economy in mind.

But I have trouble understanding why fuel injection is not a step up in technology, putting a precise amount of fuel in the right place at the right time?

Definately a lot more complicated, yes, but then again I never really learned to tune a carb well either...

69427

Most every engine I've ever seen likes about 12.5 A/F ratio for max power. That's richer than stochiometric.

I'm going to need to see some independent documentation backing up your claims.

Redeasysport

You need to rethink what you are spouting. If carbs were the same all cars would still have them they are a lot cheaper.They simply cannot control the fuel correctly though the full throttle range you have to tune them for a point they simple are not exact.

byebyeL98

IMHO, you (the OP) appear to not fully understand the benefits of electronically controlled fuel injection and the multitude of tuning parameters that can be customized for optimal performance.

devildog

If DUNTOV were still with us, he would love EFI engines.

I have a 283 FI and 283 270hp 2 x 4WCFB carbs. love them both. The engines are exactly the same. The FI (although mechanical FI) makes more hp than the dual carb.

The FI is superior, an electronic FI is a dream come true.

FICINJECTORS

Fuel injection is superior to carburetion, sure. But how? In a word, atomization. Constant, high pressure fuel forced through a tiny hole results in fuel atomization vastly superior to that of a carburetor. And since atomization is the first step in combustion, the better the fuel is atomized, the more evenly it is distributed in the cylinder, the more readily it vaporizes, and the easier it burns . All of which translate into increased cylinder filling and better combustion. The bottom line is improved throttle response and increased torque. But superior atomization isn’t the whole story. The other big deal about fuel injection is that it is able to account for all those little things affecting combustion that the carburetor’s pressure differences were blind to -- the engine’s temperature and load, for example. As a system able to deliver what the engine really needs, fuel injection far exceeds the carburetor.

aklim

I guess you and I aren't part of the "everybody" that he claims

aklim

fuel is one thing. Ignition timing is another.

65Z01

Well this ole timer has rebuilt more than one 4-b carb and the rebuild kits were on the shelf for a reason I suspect...

LarryK 87

WOW.... just WOW
i dont ever comment on grammer or spelling, or even content.... but dayum !!! thats almost like saying bias ply tires are vastly superiour to Radial tires because if i spell bad enough no one will notice how dumb it sounds.

Just WOW

Redeasysport

I didn't say anything about timing. You do know how to tune a Carb don't you? Ya know re jet to get the right A/F ratio and that is only at a static RPM if you check at different RPMs the A/F ratio will change and do so more as other changes in temp and atmosphere are factored in. All you can do with a carb is get it in the ball park and live with one setting. FI changes according to the feed back it gets form sensors.

Eddie & the Cruisers

Read this, it may change your mind.

http://carburetor-manual.com/abc-fuel-injection.php

Can you say, "how far is it from the venturi to the intake valve on cylinders 1,2,3,4,5,6,7,8 on a carbed engine compared to how far it is from any injector to the intake valve on a FI engine?"
A world of difference in the two from idle to WOT.

I loved rebuilding Rochester 4bbls on my 350's, didn't take very long, but changing injectors on a LT1 Vette is a dream come true.

Aurora40

I think anyone anywhere who has ever had a carburated car believes this. The reason is because it's true.

With all your nonsense about FI restricting air, how do you explain all the carburated engines as GM transitioned them? 350's that made less than 200hp and also got crappy fuel economy with carbs turned into slightly more powerful TBI motors that got noticeably better economy.

SAY WHEN

On the street as far as startablity-driveablity-economy-FUEL INJECTION hands down---strickly racing --NASCAR/Drag racing-- Carburetor because A)They've been around forever/it's what they know---B)They're easier for "Joe Average" to tune/work on--C) Carbs are cheaper----HOWEVER today is the age of PCs and lap tops-- guys with lap tops are doing some pretty trick things at the drag strip--in the future carburetors will likely go the way of solid rubber tires and "hand cranking"